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Database Articles
Page 417 of 546
Is there any way to see the MongoDB results in a better format?
Yes, you can use the findOne(). Following is the syntax −db.yourCollectionName.findOne();You can use toArray() as well −db.yourCollectionName.find().toArray();Let us first create a collection with documents −> db.betterFormatDemo.insertOne({"StudentName":"Adam Smith", "StudentScores":[98, 67, 89]}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7ab826d78f205348bc640") } > db.betterFormatDemo.insertOne({"StudentName":"John Doe", "StudentScores":[67, 89, 56]}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7ab936d78f205348bc641") } > db.betterFormatDemo.insertOne({"StudentName":"Sam Williams", "StudentScores":[45, 43, 33]}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7aba76d78f205348bc642") }Following is the query to display all documents from a collection with the help of find() method −> db.betterFormatDemo.find();This will produce the following output −{ "_id" : ObjectId("5cd7ab826d78f205348bc640"), "StudentName" ...
Read MoreCan we update a row with the highest ID in a single MySQL query?
Yes, we can do that. Let us first create a table −mysql> create table DemoTable ( ID int, GameScore int ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(15, 848747); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(13, 909049); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(34, 98474646); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(31, 948474); Query OK, 1 row affected (0.27 sec)Display all records from the table using select statement ...
Read MoreHow to calculate timestamp difference in hours with MongoDB?
To calculate timestamp difference, use aggregate framework. Let us first create a collection with documents −> db.timestampDifferenceDemo.insertOne({ "MovieBeginningTime": new ISODate("2019-05-12 10:20:30"), "MovieEndingTime":new ISODate("2019-05-12 12:30:20") }); { "acknowledged" : true, "insertedId" : ObjectId("5cd7ba1f6d78f205348bc644") } > db.timestampDifferenceDemo.insertOne({ "MovieBeginningTime": new ISODate("2019-05-12 04:00:00"), "MovieEndingTime":new ISODate("2019-05-12 07:10:00") }); { "acknowledged" : true, "insertedId" : ObjectId("5cd7ba3b6d78f205348bc645") }Following is the query to display all documents from a collection with the help of find() method −> db.timestampDifferenceDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cd7ba1f6d78f205348bc644"), "MovieBeginningTime" : ISODate("2019-05-12T10:20:30Z"), "MovieEndingTime" : ISODate("2019-05-12T12:30:20Z") } { "_id" : ...
Read MoreMySQL select to count values equal to 0 and greater than 0 from a column?
For this, use the CASE statement. Let us first create a table −mysql> create table DemoTable ( Number int ); Query OK, 0 rows affected (0.83 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(50); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.09 sec) mysql> insert ...
Read MoreSorted difference between two columns in MySQL?
Use ORDER BY clause for this. Let us first create a table −mysql> create table DemoTable ( Value1 int, Value2 int ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10, 40); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values(50, 5); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(51, 56); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(52, 78); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(90, 7); Query ...
Read MoreGet MAX() on column in two MySQL tables?
Use GREATEST() to find the maximum. Let us first create a table −mysql> create table DemoTable1 ( Number int ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values(80); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable1 values(229); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1 values(575); Query OK, 1 row affected (0.24 sec)Display all records from the table using select statement −mysql> select *from DemoTable1;Output+--------+ | Number | +--------+ | 80 | | 229 ...
Read MoreHow to check whether now() falls between two specific dates in MySQL?
Here, now() represents the current date. To check whether it falls between two specific dates, you need to use the BETWEEN. Let us first create a table −mysql> create table DemoTable ( FirstDate datetime, SecondDate datetime ); Query OK, 0 rows affected (0.60 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-04-01', '2019-05-02'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('2019-05-28', '2019-06-04'); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable values('2016-01-31', '2019-03-01'); Query OK, 1 row affected (0.15 sec)Display all records from the table ...
Read MoreUse ObjectId under findOne() to fetch a specific record in MongoDB?
Let us first create a collection with documents −> db.findOneWorkingDemo.insertOne({"ClientId":1, "ClientName":"Larry", "ClientAge":26}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7c1716d78f205348bc64d") } > db.findOneWorkingDemo.insertOne({"ClientId":2, "ClientName":"Chris", "ClientAge":28}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7c17d6d78f205348bc64e") } > db.findOneWorkingDemo.insertOne({"ClientId":3, "ClientName":"Robert", "ClientAge":34}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7c1896d78f205348bc64f") }Following is the query to display all documents from a collection with the help of find() method −> db.findOneWorkingDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cd7c1716d78f205348bc64d"), "ClientId" : 1, "ClientName" : "Larry", "ClientAge" : 26 } { "_id" : ObjectId("5cd7c17d6d78f205348bc64e"), "ClientId" : 2, ...
Read MoreMySQL ORDER BY with different ordering for some of the values as descending and others ascending?
You can use the field() for this. Let us first create a table −mysql> create table DemoTable ( Value int ); Query OK, 0 rows affected (0.80 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(70); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(60); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(56); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(81); Query OK, 1 row affected (0.44 sec) mysql> ...
Read MoreCombining multiple rows into a comma delimited list in MySQL?
To combine multiple rows into a comma delimited list, use the GROUP_CONCAT() method. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Name varchar(30), Marks int ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Name, Marks) values('John', 67); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable(Name, Marks) values('Carol', 69); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable(Name, Marks) values('Sam', 69); Query OK, 1 row affected (0.12 sec) mysql> insert ...
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